Press releases Monday 23 March to Friday 27 March 2009

Please remember to credit the BMJ as source when publicising an article and to tell your readers that they can read its full text on the journal's website (http://www.bmj.com).

(1) Study reports long-term health of Porton Down veterans
(2) Eating during labour has no effect on delivery
(3) Pregnant women who smoke, urged to give up before 15 week "deadline"
(4) Drinking very hot tea can increase the risk of throat cancer
(5) Doctors differ on whether hospices should follow CPR guidelines
(6) Concern over inappropriate diagnosis and treatment of thyroid problems

(1) Study reports long-term health of Porton Down veterans
(Mortality in British military participants in human experimental research into chemical warfare agents at Porton Down: cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b613
(Cancer morbidity in British military veterans included in chemical warfare agent experiments at Porton Down: cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b655
(Editorial: Mortality and cancer in Porton Down subjects)
http://www.bmj.com/cgi/doi/10.1136/bmj.b358

Members of the UK armed forces who took part in chemical tests at Porton Down were at a slightly increased risk of death between 1941 and 2004 compared to military personnel who were not included in the tests, but they were not at increased risk of cancer, finds a study published on bmj.com today.

Between 1941 and 1989, over 18,000 members of the armed forces took part in a research programme at the chemical defence establishment at Porton Down. The effects on their long-term health have not been studied previously. Many toxic chemicals were used in the tests and over half of these veterans were recorded as taking part in tests involving chemicals that are known or probable human carcinogens

In this first study to follow up the cohort of Porton Down veterans, a research team led by Dr Lucy Carpenter and Dr Katherine Venables assessed whether the risks of death and cancer were higher in veterans who took part in tests compared with those who did not.

The study tracked death rates among 18,276 Porton Down veterans and 17,600 non-Porton Down veterans for an average of over 40 years. Test records were used to assess type of chemical and the NHS Central Register was used to identify deaths registered before 31 December 2004.

Over 7,000 of the Porton Down veterans had died by the end of 2004 and their overall death rates were 6% higher than non-Porton Down veterans. Looking at deaths according to cause, the following were raised in Porton Down veterans: infectious and parasitic diseases, genitourinary causes, circulatory diseases, and external (non-medical) causes. Deaths which occurred overseas were also raised in Porton Down veterans.

Importantly, the research team found no increase in cancer deaths. Information on cancer was available for 17,013 Porton Down veterans and a similar group of 16,520 non-Porton Down veterans. The NHS Central Register was used to identify all cancers from 1971 to 2004.

Over 3,000 cancers were registered in Porton Down veterans and overall cancer rates were the same as in non-Porton Down veterans.

Porton Down veterans did have higher rates of certain ill-defined or pre-cancerous neoplasms but no evidence of an excess of any specific, clearly defined malignant cancer.

This large study with detailed chemical exposure information provides insights into the long-term health of Porton Down veterans, say the authors. However, with the lack of information about lifestyle factors, most importantly smoking, it is not possible to attribute the small excess mortality to chemical exposures at Porton Down, or to other factors, they conclude. The same argument applies to the excess of ill-defined cancers.

The mortality and cancer rates of Porton Down and non-Porton Down veterans were lower than those of the general population. This is a common finding in employed groups, especially members of the armed forces, who have to pass health and fitness tests before recruitment.

The findings of these two studies should provide some reassurance to Porton Down veterans and their supporters, writes Professor Malcolm Sim from Monash University in Melbourne, Australia, in an accompanying editorial. The excess risk of major causes of death was small and there was no overall increased risk of cancer.

Although human carcinogens were used in the Porton Down experiments, the cumulative doses received were probably small compared with industrial exposure in manufacturing facilities, and - as the study found - too low to cause a measurable excess of cancer.

The overall findings are consistent with other studies and remain an important area of future research and public interest, he concludes.

Contacts:
Research: Dr Lucy Carpenter and Dr Katherine Venables, Department of Public Health, University of Oxford, UK
Email: press.office@headoffice.mrc.ac.uk

Editorial: Professor Malcolm Sim, Director, Monash Centre for Occupational and Environmental Health, Monash University, Melbourne, Australia
Email: malcolm.sim@med.monash.edu.au


(2) Eating during labour has no effect on delivery
(Research: Effect of food intake during labour on obstetric outcome: randomised controlled trial)
http://www.bmj.com/cgi/doi/10.1136/bmj.b784
(Editorial: Eating a light diet during labour)
http://www.bmj.com/cgi/doi/10.1136/bmj.b732

Eating during labour does not affect delivery, according to a study published on bmj.com today. It also has no effect on the duration of labour, the need for assisted delivery (forceps or vacuum extraction), or caesarean rates.

Since the 1940s, it has been common practice to prevent women from eating during labour to minimise the risk of pulmonary aspiration (breathing food into the lungs) in women who may need an emergency caesarean under general anaesthetic.

But pulmonary aspiration has declined dramatically in recent years, mainly due to the increased use of local anaesthesia for caesarean deliveries. Furthermore, some doctors and midwives argue that preventing food intake during labour can be detrimental to the mother, her baby, and the progress of labour, so the policy of routine fasting is being increasingly challenged.

Results from five previous trials of food intake during labour have been inconclusive, so a research team led by Professor Andrew Shennan at King's College London set out to investigate the effect of eating during labour on delivery rates.

The study took place at Guy's and St Thomas' Hospital in London between June 2001 and April 2006 and involved 2,426 healthy women, having their first baby.

Women were randomly split into an "eating" group or a "water only" group. The eating group were advised to eat small regular amounts of food, such as bread, biscuits, fruits, low fat yoghurt, isotonic drinks, and fruit juice. The water only group were advised to have ice chips and water only.

Age, ethnicity, food intake for six hours before and during labour, vomiting and the need for intravenous fluids were recorded.

The spontaneous vaginal delivery rate was the same in both groups (44%). There were also no clinically significant differences in duration of labour (597 minutes for the eating group and 612 minutes for the water group), caesarean delivery rate (29% for the eating group and 30% for the water group), or vomiting (35% for the eating group and 34% for the water group).

There were also no differences in the condition of the babies at birth or admission to special care units.

These findings show that eating does not shorten labour, nor does it increase the chance of a normal delivery, so withholding food is not detrimental, say the authors. However, eating and drinking may allow mothers to feel normal and healthy, so the policy of routine fasting during labour is not justified, they conclude.

These results offer the best evidence yet in this area, and reinforce the most recent guidelines from the National Institute for Clinical Excellence (NICE) that low risk women in normal labour may eat and drink, says Professor Soo Downe from the University of Central Lancashire in an accompanying editorial.

Future research could investigate women's views and experiences of eating and drinking during labour, and the effect of a policy of a light diet on outcomes in other settings, she concludes.

Contacts:
Research: Andrew Shennan, Professor of Obstetrics, Maternal and Fetal Research Unit, King's College London, UK
Email: andrew.shennan@kcl.ac.uk

Editorial: Soo Downe, Director, Research in Childbirth and Health Group (ReaCH), University of Central Lancashire, Preston, Lancashire, UK
Email: sdowne@uclan.ac.uk

(3) Pregnant women who smoke, urged to give up before 15 week "deadline"
(Spontaneous preterm birth and small for gestational age infants in women who cease smoking in early pregnancy: a prospective cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b1081

Women who stop smoking before week 15 of pregnancy cut their risk of spontaneous premature birth and having small babies to the same as non-smokers, according to research published on bmj.com today.

Women who do not quit by 15 weeks, are three times more likely to give birth prematurely and twice as likely to have small babies compared to women who have stopped smoking, say the researchers. The lead author, Dr Lesley McCowan at the University of Auckland, says that maternity care providers need to emphasise to women the major benefits of giving up smoking before 15 weeks in pregnancy with the goal of becoming smoke free as early in pregnancy as possible.

While it is well established that smoking in pregnancy increases the risk of miscarriage, ectopic pregnancy, premature birth, small babies, stillbirth and neonatal death, say the authors, no study has yet determined whether stopping smoking in early pregnancy reduces the risks of small babies and premature births.

The authors surveyed over 2,500 pregnant women participating in the SCOPE study in Australia and New Zealand at 15 weeks gestation. The participants were divided into three groups: non smoker, stopped smoker and current smoker. The ‘stopped smoker' group all gave up before 15 weeks of pregnancy.

The results show that there were no differences between the rates of premature birth between stopped smokers and non-smokers, whereas current smokers had much higher risk. Similar results were revealed for expected baby size.

Another important finding was that women who stopped smoking were not more stressed than women who continued to smoke.

The smoking status of the participants also revealed social and health inequalities. Smokers were more likely to be single mothers, less well educated, unemployed, overweight or underweight. They were more likely to be drinking alcohol and less likely to be taking folic acid at 15 weeks of pregnancy.

In conclusion, the authors say that their "results are of considerable public health importance. The data suggest that the adverse effects of smoking on these late pregnancy outcomes may be largely reversible if smoking is ceased early in pregnancy, offering an important incentive for pregnant women who smoke to become smoke-free early in pregnancy."

Contacts:
Dr Lesley McCowan, Associate Professor of Obstetrics and Gynaecology, Department of Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand
Email: l.mccowan@auckland.ac.nz

(4) Drinking very hot tea can increase the risk of throat cancer
(Tea drinking habits and oesophageal cancer in a high risk area in Northern Iran: population based case-control study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b929
(Editorial: Hot tea and increased risk of oesophageal cancer)
http://www.bmj.com/cgi/doi/10.1136/bmj.b610

People are advised to wait a few minutes before drinking a cup of freshly-boiled tea today as a new study, published on bmj.com, finds that drinking very hot tea (70°C or more) can increase the risk of cancer of the oesophagus, the muscular tube that carries food from the throat to the stomach.

The study was carried out in northern Iran, where large amounts of hot tea are drunk every day.

But an accompanying editorial says these findings are not cause for alarm and the general advice is to allow foods and beverages to cool a little before swallowing.

Cancers of the oesophagus kill more than 500,000 people worldwide each year and oesophageal squamous cell carcinoma (OSCC) is the commonest type. In Europe and America, it is mainly caused by tobacco and alcohol use and is more common in men than in women, but drinking hot beverages is also thought to be a risk factor.

Golestan Province in northern Iran has one of the highest rates of OSCC in the world, but rates of smoking and alcohol consumption are low and women are as likely to have a diagnosis as men. Tea drinking, however, is widespread, so researchers set out to investigate a possible link between tea drinking habits and risk of OSCC.

They studied tea drinking habits among 300 people diagnosed with OSCC and a matched group of 571 healthy controls from the same area. Nearly all participants drank black tea regularly, with an average volume consumed of over one litre a day.

Compared with drinking warm or lukewarm tea (65°C or less), drinking hot tea (65-69°C) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70°C or more) was associated with eight-fold increased risk.

Likewise, compared with drinking tea four or more minutes after being poured, drinking tea less than two minutes after pouring was associated with a five-fold higher risk.

There was no association between the amount of tea consumed and risk of cancer.

To minimise errors between reported and actual tea temperatures, the researchers then measured the actual temperature that tea was consumed by nearly 50,000 residents of the same area. This ranged from less than 60°C to more than 70°C and there was a moderate agreement between reported tea drinking temperature and actual temperature measurements.

Our results show a strong increase in the risk of oesophageal squamous cell carcinoma associated with drinking hot or very hot tea, say the authors.

Previous studies from the United Kingdom have reported an average temperature preference of 56-60°C among healthy populations.

They suggest that informing the population about the hazards of drinking hot tea may be helpful in reducing the incidence of oesophageal cancer in Golestan and in other high risk populations where similar habits are prevalent.

These results provide persuasive evidence that drinking tea at temperatures greater than 70°C markedly increases the risk of oesophageal squamous cell carcinoma, says David Whiteman from the Queensland Institute of Medical Research in Australia in an accompanying editorial.

This report also lends support to the notion that thermal injury may be a cause of epithelial cancers, though he points out that the way in which heat promotes tumour development is not clear and warrants further investigation.

However, he stresses that these findings are not cause for alarm, and they should not reduce public enthusiasm for the time honoured ritual of drinking tea. Instead he suggests waiting at least four minutes before drinking a cup of freshly boiled tea, or more generally allowing foods and beverages to cool from "scalding" to "tolerable" before swallowing.

An accompanying video features interviews with some of the researchers as well as original footage from Iran in the early days of the study.

Contacts:
Research: Reza Malekzadeh, Professor and Director, Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
Email: malek@ams.ac.ir

Editorial: David Whiteman, Head, Cancer Control Laboratory, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Queensland, Australia
Email: david.whiteman@qimr.edu.au

(5) Doctors differ on whether hospices should follow CPR guidelines
(Head to Head: Should hospices be exempt from following national cardiopulmonary resuscitation guidelines?)
Yes http://www.bmj.com/cgi/doi/10.1136/bmj.b965

No http://www.bmj.com/cgi/doi/10.1136/bmj.b986

Experts in two papers published on bmj.com today disagree on whether cardiopulmonary resuscitation (CPR) guidelines should apply to hospices.

Dr Max Watson and colleagues believe that CPR is not always appropriate for patients who are dying and that hospices should be able to develop their own guidelines. However, Drs Claud Regnard and Fiona Randall argue that it is "inconceivable" that hospices should seek exemption from the good practice set out in the UK guidelines.

Watson says that blanket rules on CPR do not work in hospices because the needs of these patients are unique. In a hospice "the goal for the majority is quality of life and a dignified death", he argues. Dr Watson goes further and says that full CPR facilities are often not possible in hospices and that it is disingenuous to discuss this issue with patients when only basic life support equipment and training may be available.

In conclusion, Watson calls for specific hospice guidelines that are clear, simple and robust and that one national policy for both the acute and the hospice sector is too ambitious.

But Regnard and Randall believe that the current guidelines "uphold essential core principles and values that particularly apply in end of life care." They argue that the guidelines provide essential protection for patients and that it makes no sense to seek exemption from them. For example, the guidelines protect patients from arbitrary discrimination, safeguard a patient's right to receive or refuse CPR, and protect dying patients.

Regnard and Randall also argue that CPR decisions are determined by what is in the patient's best interest. Therefore if a patient lacked capacity and was unable to survive CPR then the procedure would not go ahead, "these safeguards are essential to prevent unnecessary distress for patients, partners, and relatives at the end of life," they say.

"Working to different rules in hospices would result in confusion, exclude hospice patients from recognised good practice, and would seriously compromise working partnerships with colleagues in other settings. Exemption would create poorer, and thus inequitable, care for hospice patients," they conclude.

Contacts:
Dr Max Watson, Consultant in Palliative Medicine, Northern Ireland Hospice Belfast, UK
Email: max.watson@nihospicecare.com

Dr Claud Regnard, Consultant in Palliative Medicine, St Oswald's Hospice and Newcastle Hospitals NHS Trust
Email: claudregnard@stoswaldsuk.org

(6) Concern over inappropriate diagnosis and treatment of thyroid problems
(Editorial: Diagnosis and treatment of primary hypothyroidism)
http://www.bmj.com/cgi/doi/10.1136/bmj.b725

More and more people are being inappropriately diagnosed and treated for underactivity of the thyroid gland (known as primary hypothyroidism), warn doctors in an editorial published on bmj.com today.

Hypothyroidism is caused by insufficient production of thyroid hormone by the thyroid gland. It affects about three per cent of the population and is usually treated in primary care. Blood tests are essential in confirming the diagnosis of hypothyroidism.

But doctors at the British Thyroid Association are concerned that, in recent years, increasing numbers of patients with and without confirmed thyroid disease have been diagnosed and treated inappropriately with thyroid hormones.

"This is potentially an enormous problem, given that in any one year one in four people in the United Kingdom have their thyroid function checked," they warn.

The Royal College of Physicians recently set out clear guidance for the diagnosis and treatment of primary hypothyroidism in the United Kingdom, so why have these problems arisen, ask the authors?

Hypothyroidism is common and is becoming more prevalent because of increased life expectancy and an ageing population, they explain. Thyroid hormones also affect most organs, so hypothyroidism presents with symptoms that can mimic other conditions. This can lead to an incorrect diagnosis which could expose some patients to the harmful effects of excess thyroid hormones, while other serious conditions may go undiagnosed.

Information available on the internet and media interest in alternative modes of diagnosis and treatment of hypothyroidism, have also caused an increase in requests for inappropriate investigations and non-standard treatments, as well as referrals to non-accredited practitioners, they add.

These factors have led to a rise in awareness and confusion about hypothyroidism, and they have increased the workload in primary care.

The authors stress that, in most cases, the management of primary hypothyroidism is straightforward and should be undertaken in primary care.

But they suggest that if wellbeing is not restored despite normal concentrations of thyroid stimulating hormone, it is important to exclude other conditions as the cause of ongoing symptoms. If no obvious cause is found the patient should be referred to an accredited hospital endocrinologist or general physician.

Contacts:
Amit Allahabadia, Secretary, British Thyroid Association, Department of Endocrinology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, UK
Email: amit.allahabadia@sth.nhs.uk

FOR ACCREDITED JOURNALISTS

Embargoed press releases and articles are available from:

Public Affairs Division, BMA House, Tavistock Square London WC1H 9JR

(contact: pressoffice@bma.org.uk)

and from:

the EurekAlert website, run by the American Association for the Advancement of Science (http://www.eurekalert.org)